Adhesions may be present at birth (congenital) or may form after abdominal surgery or inflammation. Most form after surgery. Adhesions are more common after procedures on the colon, appendix, or uterus than after surgery on the stomach, gall bladder, or pancreas. The risk of developing adhesions increases with the passage of time after the surgery.
Abdominal adhesions are bands of fibrous scar tissue that form on organs in the abdomen, causing the organs to stick to one another or to the wall of the abdomen. Intestinal adhesions are bands of fibrous tissue that connect the loops of the intestines to each other, or the intestines to other abdominal organs, or the intestines to the abdominal wall. These bands can pull sections of the intestines out of place and may block passage of food. In people living in developed countries, this scar tissue most commonly develops after abdominal surgery, in which organs are handled by the surgical team and are shifted temporarily from their normal positions. It can also form in people who develop peritonitis, an infection that has spread to the membrane that covers the abdominal organs. Peritonitis commonly occurs after appendicitis or other abdominal infections. Another cause of adhesions is endometriosis, an inflammatory condition that affects some women and may involve the abdomen and serious abdominal trauma, including cesarean sections.
Adhesions are a major cause of intestinal obstruction. If the adhesions cause partial or complete obstruction of the intestines, the symptoms exhibited depend on the degree and the location of the obstruction. They include cramps, abdominal pain, vomiting, bloating, an inability to pass gas, and constipation. In a small number of people who have adhesions, however, the fibrous bands of scar tissue block the intestines either completely or partially. This blockage is called a bowel obstruction, and leads to death in about 5% of cases. Sometimes, an area of intestine that is affected by adhesions can become blocked then unblocked, causing symptoms to come and go. In about 10% of small-bowel obstructions, a portion of the bowel twists tightly around a band of adhesions. This cuts off the normal blood supply to the twisted bowel, a disorder known as strangulation, causing that section of bowel to die. When this emergency happens, the person must undergo surgery immediately. The death rate is as high as 37% in people who develop strangulation.
Percutaneous epidural adhesiolysis and spinal endoscopic adhesiolysis are interventional pain management techniques used to treat patients with refractory low back pain due to epidural scarring. Standard epidural steroid injections are often ineffective, especially in patients with prior back surgery. Adhesions in the epidural space can prevent the flow of medicine to the target area; lysis of these adhesions can improve the delivery of medication to the affected areas, potentially improving the therapeutic efficacy of the injected medications. Prevention of such adhesions would be more preferable.
Many different materials have been tried as a means of preventing adhesions. Most of these are hydrogels that are applied as solutions at the time of surgery. Efficacy of these materials has varied due to rapid degradation and/or failure to form a sufficiently thick barrier. Others materials work only in combination with anti-proliferative drugs. None of these materials has been shown to be effective work in a highly fluid environment, which usually is present during surgery due to bleeding and leakage of other bodily fluids.
It is therefore an object of the present invention to provide methods and compositions for preventing or minimizing adhesions and for other barrier applications which can be applied to tissues or cells which are bleeding or in the presence of fluids.
It is another object of the present invention to provide such a composition that can be formulated as a bandage, spray, coating, or powder.
It is a still further object of the present invention to provide a composition that can be used to retain fluids or cells but is sufficiently clear to allow a physician to see and work through the material.